Synthesis and characterization of 4-methyl-1-(3-sulfopropyl)pyridinium hydrogen sulfate as a new ionic liquid immobilized on silica nanoparticles: A recyclable nanocomposite ionic liquid for the production of various substituted phthalazine-ones

Abstract

4-Methyl-1-(3-sulfopropyl)pyridinium hydrogen sulfate ([MSPP][HSO4]) as a new acidic ionic liquid was prepared in a quick and easy process, and characterized by some techniques such as 1H NMR, 13C NMR and FT-IR analysis. Then, [MSPP][HSO4] was immobilized on silica nanoparticles by impregnation method to afforded heterogeneous acidic ionic liquid ([MSPP]HSO4@nSiO2) and characterized by elemental analysis (CHNS), FT-IR, and SEM. The worthiness of [MSPP]HSO4@nSiO2 has been investigated for the synthesis of various substituted phthalazine-ones as well as selective synthesis of mono- and bis-phthalazine-ones as imperative biologically active compounds. The reaction has been carried out under solvent-free conditions, simple work-up procedure and the products were obtained in excellent to good yields. Moreover, the catalyst was reused five times without decay in catalytic activity performance. © 2018 Elsevier B.V.